Prevalence of Multidrug-Resistant UPEC in the United States
The prevalence of multidrug-resistant (MDR) uropathogenic E. coli in the United States has decreased slightly from approximately 13% to 12% between 2016-2021, with current rates around 12% in outpatient settings. 1
Current Prevalence Data
The most recent and comprehensive U.S. data shows:
- Overall MDR prevalence is 12% as of 2021 in outpatient uncomplicated UTIs, representing a modest decline from 13% in 2016 1
- MDR is defined as resistance to ≥3 antibiotic classes 1
- Approximately 50% of UPEC isolates remain susceptible to all tested antibiotics 1
Resistance Distribution by Number of Classes
- Single-class resistance: 19% of isolates 1
- Two-class resistance: 18% of isolates 1
- Three-class resistance: 8% of isolates 1
- Four-class resistance: 4% of isolates 1
- Five or more classes: 1% of isolates 1
Most Common Resistance Patterns
The predominant MDR phenotype involves penicillins and trimethoprim-sulfamethoxazole (TMP-SMX), with or without additional classes:
- Penicillin resistance overall: 29% of isolates 1
- Co-resistance to penicillins and TMP-SMX: 12% 1
- MDR involving penicillins, TMP-SMX, plus ≥1 additional class: 10% 1
Historical data from 2000 showed the classic MDR phenotype (ampicillin, cephalothin, and TMP-SMX) comprised 57.9% of all MDR isolates 2, though overall MDR rates were lower at 7.1% nationally 2
High-Risk Patient Demographics
MDR rates are significantly elevated in specific populations:
- Males: 10.4% versus females at 6.6% 2
- Patients >65 years: 8.7% compared to 6.8% in those ≤17 years and 6.1% in ages 18-65 2
- Inpatients: 7.6% versus outpatients at 6.9% 2
Geographic Variation
Regional differences exist within the United States:
- West South Central region: highest at 9.2% 2
- West North Central region: lowest at 4.3% 2
- Spatial clustering of specific ST lineages (particularly ST131, ST95, ST69) occurs within communities, suggesting common-source transmission rather than purely antimicrobial selection pressure 3
Clinical Implications
The decreasing trend in MDR prevalence is encouraging but resistance remains substantial:
- The decline from 13% to 12% over 5 years represents a statistically significant but clinically modest improvement 1
- Resistance patterns are consistent across both in-person and virtual care settings, validating telemedicine approaches for UTI management 1
- ST131 lineage contributes disproportionately to MDR cases, with 40% of ST131 isolates being multidrug-resistant 3
Common Pitfalls
- Do not assume low MDR rates mean individual antibiotics are effective - single-class resistance affects 19% of isolates, meaning nearly 1 in 5 patients will fail first-line monotherapy if susceptibility is not considered 1
- Male patients and elderly populations require heightened suspicion for MDR given their 1.5-fold higher rates 2
- Geographic location matters - clinicians in the West South Central region face double the MDR prevalence compared to the West North Central region 2